Anti-lymphocyte therapy successfully controls late "cholestatic" rejection in pediatric liver transplant recipients

T-cell infiltrate intensity is associated with delayed response to treatment in late acute cellular rejection in pediatric liver transplant recipients

BACKGROUND

Late acute cellular rejection (ACR) is associated with donor-specific antibodies (DSA) development, chronic rejection, and allograft loss. However, accurate predictors of late ACR treatment response are lacking. ACR is primarily T-cell mediated, yet B cells and plasma cells (PC) also infiltrate the portal areas during late ACR. To test the hypothesis that the inflammatory milieu is associated with delayed response (DR) to rejection therapy, we performed a single-center retrospective case-control study of pediatric late liver ACR using multiparameter immunofluorescence for CD4, CD8, CD68, CD20, and CD138 to identify immune cell subpopulations.

METHODS

Pediatric liver transplant recipients transplanted at <17 years of age and treated for biopsy-proven late ACR between January 2014 and 2019 were stratified into rapid response (RR) and DR based on alanine aminotransferase (ALT) normalization within 30 days of diagnosis. All patients received IV methylprednisolone as an initial rejection treatment. Immunofluorescence was performed on archived formalin-fixed paraffin embedded (FFPE) liver biopsy tissue.

RESULTS

Liver biopsies from 60 episodes of late ACR in 54 patients were included in the analysis, of which 33 were DR (55%). Anti-thymocyte globulin was only required in the DR group. The frequency of liver-infiltrating CD20+ and CD8+ lymphocytes and the prevalence of autoantibodies were higher in the DR group. In univariate logistic regression analysis, serum gamma-glutamyl transpeptidase (GGT) level at diagnosis, but not ALT, Banff score or presence of DSA, predicted DR.

CONCLUSIONS

Higher serum GGT level, presence of autoantibodies, and increased CD8+ T-cell infiltration portends DR in late ACR treatment in children.

Efficacy of Antithymocyte Globulin Treatment for Severe Centrilobular Injury Following Pediatric Liver Transplant: Clinical Significance of Monitoring Lymphocyte Subset

OBJECTIVES

Central perivenulitis can occur in association with T-cell-mediated rejection and can sometimes require strong immunosuppressant therapy as refractory rejection. Furthermore, patients with central perivenulitis are more likely to have subsequent episodes of T-cell-mediated rejection and develop chronic rejection than those without central perivenulitis. We retrospectively analyzed clinical data of pediatric patients with episodes of T-cell-mediated rejection according to severity of central perivenulitis and monitored HLA-DR-positive CD8-positive T cells and recent thymic emigrants during treatment for T-cell-mediated rejection.

MATERIALS AND METHODS

We identified biopsy-proven T-cell-mediated rejection in 50 liver transplant recipients (45 with living-related donors, 5 with deceased donors) between September 2014 and August 2018. Lymphocyte subsets in peripheral blood samples were analyzed.

RESULTS

Of 50 pediatric patients, 30 were boys and 20 were girls (median age at transplant of 1.1 y; interquartile range, 0.6-6.2 y). Central perivenulitis was found in 46 patients (92%), which was mild in 13, moderate in 16, and severe in 17. Antithymocyte globulin was more frequently administered to patients with severe central perivenulitis than others (P < .05). Patients with antithymocyte globulin treatment were less likely to have subsequent episodes of T-cell-mediated rejection than those without this treatment (P < .05). The absolute number of CD8-positive HLA-DR-positive T cells in patients during treatment was significantly higher than in control patients (P < .05). The absolute number of recent thymic emigrants in patients with active infection was significantly lower than in patients without infection (P < .05).

CONCLUSIONS

Our results suggest the efficacy and safety of antithymocyte globulin for treating T-cell-mediated rejection with severe central perivenulitis in pediatric liver transplant recipients and suggest that antithymocyte globulin can prevent subsequent episodes of T-cell-mediated rejection. Analyzing lymphocyte subsets during treatment for rejection may help highlight viable therapeutic strategies for achieving a good outcome.

Antibody Drug Treatment for Steroid-Resistant Rejection After Pediatric Living Donor Liver Transplantation: A Single-Center Experience

BACKGROUND

Antibody drugs have been used to treat steroid-resistant rejection (SRR) after liver transplantation. Although anti-thymocyte globulin has been used for SRR after liver transplantation in place of muromonab-CD3 since 2011 in Japan, the effectiveness of anti-thymocyte globulin after pediatric living-donor liver transplantation (LDLT) has not yet been reported. The aim of this study was to evaluate the effectiveness of antibody drug treatment for SRR after pediatric LDLT in our single center.

METHODS

Between May 2001 and December 2013, 220 pediatric LDLTs were performed. Initial immunosuppression after LDLT included tacrolimus and methylprednisolone therapy. Acute rejection was diagnosed by use of a liver biopsy and the administration of steroid pulse treatment, and SRR was defined as acute rejection refractory to the steroid pulse treatment.

RESULTS

Acute rejection and SRR occurred in 74 (33.6%) and 16 patients (7.3%), respectively. The graft survival rates of non-SRR and SRR were 92.4% and 87.5%, respectively (P = .464). The median concentration of alanine aminotransferase before and after the administration of antibody drug was 193.5 mU/mL (range, 8-508) and 78 mU/mL (range, 9-655), respectively (P = .012). The median rejection activity index before and after the administration of antibody drugs was 5 (range, 2-9) and 1 (range, 0-9), respectively (P = .004). After antibody drug treatment, 12 patients had cytomegalovirus infections, 2 patients had Epstein-Barr virus infections, 3 patients had respiratory infections, and 1 patient had encephalitis. The cause of death in 1 patient with SRR was recurrence of infant fulminant hepatic failure.

CONCLUSIONS

Antibody drug treatment for SRR after pediatric LDLT is safe and effective.

Immunosuppression in the pediatric transplant recipient

The field of pediatric solid-organ transplantation has significantly evolved since its beginnings in the early 20^th century. As advancements have led to the development of innovative surgical techniques and novel medication regimens, transplantation has now become a routine practice leading to an increase in the rates of organ recipients worldwide. The care of pediatric solid-organ transplant recipients differs from adults in several areas not only due to technically challenging surgeries, but mostly due to the complexity of their immunosuppression management. Although there is large variation of pediatric immunosuppression regimens worldwide, the use of calcineurin inhibitors, either tacrolimus or cyclosporine, still forms the backbone of immunosuppression regimens after solid-organ transplantation. Both medications are relatively well tolerated but are known to have long-term side effects, especially nephrotoxicity and neurotoxicity. The goal of care in long-term pediatric survivors of solid-organ transplant now aims to safely minimize exposure to immunosuppression and to achieve long-term graft tolerance.

Liver allograft biopsies with histological cholestasis: a clinicopathological study of 254 cases from a single centre

AIMS

Liver allograft biopsy is important in the management of liver transplant (LT) recipients. Cholestasis is an indicator of liver dysfunction, and histological evidence of cholestasis can be observed in a wide range of pathological entities in the post-LT setting. In this study, we describe the clinicopathological features and significance of liver allograft biopsies with histological cholestasis over 11 years in our centre.

METHODS

Liver allograft biopsies performed in Queen Mary Hospital, Hong Kong from 2004 to 2014 showing histological cholestasis were retrieved from the pathology archive. Clinical and pathological data were retrospectively reviewed and analyzed.

RESULTS

Among the 254 biopsies from 167 patients, large duct obstruction (LDO) and acute cellular rejection (ACR) were the two main aetiologies associated with cholestasis. There was a decrease in sepsis as a cause over the study duration. In cases showing cholestasis at 6 months or more after LT, LDO was more common than ACR. Over half (61%) of the 254 biopsies showed mild cholestasis. Severe panacinar cholestasis was more often observed in LDO. Mild cholestasis was most commonly observed regardless of the severity of ACR. Severe cholestasis was associated with poorer 1-year and 3-year graft survival and patient survival, as well as higher 3-month and 6-month post-biopsy mortality.

CONCLUSION

Histological cholestasis and its severity in liver allograft biopsies has clinical and prognostic significance. Our study summarizes our previous experience and provides further insights into the management of post-LT patients.

Basiliximab treatment for steroid-resistant rejection in pediatric patients following liver transplantation for acute liver failure

An IL-2 receptor antagonist, basiliximab, decreases the frequency of ACR in liver transplant (LT) recipients as induction therapy. The aim of this study was to evaluate the effectiveness of basiliximab against SRR as rescue therapy in pediatric LT patients with ALF. Forty pediatric ALF patients underwent LT between November 2005 and July 2013. Among them, seven patients suffering from SRR were enrolled in this study. The median age at LT was 10 months (6-12 months). SRR was defined as the occurrence of refractory rejection after more than two courses of steroid pulse therapy. Basiliximab was administered to all patients. The withdrawal of steroids without deterioration of the liver function was achieved in six patients treated with basiliximab therapy without patient mortality, although one patient developed graft loss and required retransplantation for veno-occlusive disease. The pathological examinations of liver biopsies in the patients suffering from SRR revealed severe centrilobular injuries, particularly fibrosis within one month after LT. We demonstrated the effectiveness and safety of rescue therapy consisting of basiliximab for SRR in pediatric LT recipients with ALF.

Management of acute rejection in paediatric liver transplantation

The success of paediatric liver transplantation is attributed to improved surgical techniques and the advent of calcineurin inhibitor-based immunosuppression. Acute rejection (AR) rarely results in graft loss with calcineurin inhibitor immunosuppressive regimens, and the advent of newer agents like interleukin (IL)-2 receptor antibodies. The latter have the benefit of reducing the incidence of AR further and may be of use in patients who are susceptible to recurrent AR, were retransplanted for graft rejection or are in a steroid-sparing regimen. A total of 60 % of all paediatric liver transplants result in AR; however, there is a 75 % response rate to initial steroid therapy. Steroid therapy remains the mainstay of initial AR management, coupled with an increase in baseline immunosuppression. Steroid-resistant rejection (SRR), previously an immediate indication for potent anti-lymphocyte preparations, is now effectively treated with chimeric or humanised IL-2 receptor monoclonal antibodies. Recurrent AR can be treated by adding adjuvant immunosuppressive agents such as mycophenolate mofetil (MMF) or sirolimus. Studies have also demonstrated the efficacy of MMF as rescue therapy for SRR. Anti-lymphocyte preparations such as anti-thymocyte globulin (ATG) and OKT3 are rarely used in SRR but may be of use as rescue therapy for severe SRR. The challenges of the management of AR remain in the management of recurrent AR and SRR. We discuss the pathogenesis, diagnosis and management of AR, including prevention, and specific management of AR and SRR based on current evidence and our own experience at the King's College Paediatric Liver, Gastroenterology and Nutrition Centre in London.

Induction immunosuppression in liver transplantation: a review

Antibody therapy for induction is seldom used in liver transplantation in the United States, but continues to be used in approximately 10% of patients. The most commonly used antibody at the current time is basiliximab (Simulect, Novartis) and is used in adults with renal dysfunction at the time of liver transplantation with the intention of delaying introduction of calcineurin-inhibitors. In children, the same antibody is commonly used in order to reduce rates of acute rejection. Most patients, adult and pediatric, are treated with initially higher levels of tacrolimus rather than antibody induction.